The arts have conventionally proposed converting colors to data in a standard color space thereby to improve color reproducibility. For example, Patent Literature 1 discloses an art that converts an individual color to data in an RGB (Red, Green, Blue) color space, data in a CYMK (Cyan, Yellow, Magenta, Black) color space or the like thereby to improve color reproducibility.
In this way, systems for quantitatively expressing colors include RGB representation, CYMK representation, as well as HSV (Hue, Saturation/chroma, Value/brightness) representation and the like. Conversion of values among the respective systems is formulated.
In RGB representation, 24 bit color, in which a color is represented by 3 bytes, is widely used. In 24 bit color, any one of 0 to 255 is assigned to each component of R, G, B. In 15 bit color in which a color is represented by 2 bytes, any one of 0 to 31 is assigned to each component of R, G, B. By dividing the respective components of R, G, B in 24 bit color by 8, 24 bit color can be converted to 15 bit color.
In this way, accuracy (resolution) of color space relative to data representation will be properly selected. A color represented with a high accuracy will be converted to a color with a low accuracy although information of the color is decreased.